Conventionally, there is known a fancy hair dyeing method called TIP color, comprising changing a color tone of only a tip portion of hair, to provide an peculiar appearance. The TIP color provides a fancy appearance such as having a color tone change of a gradation effect of gradually changing the color toward a tip portion of hair.
As a method for imparting a color to a head of the user without directly dyeing the hair, there is known a method of attaching a hair ornament called an extension to a head of the user. A colored extension is obtained by forming an artificial hair fiber bundle constituted of colored synthetic fibers or a like material.
Whereas multitudes of kinds of colored extensions are well-known, there is scarcely known an extension having TIP color, i.e. an extension having a color tone change with a gradation appearance.
As a technique of stepwise changing the color tone of an artificial hair fiber bundle, for instance, patent document 1 describes a doll's hair fiber which is produced by applying different color dyeing liquids, as an aqueous medium, to an intended portion to be dyed of a fiber bundle being bundled and fixed of one end thereof; and subjecting the portion of the fiber bundle to dielectric heating using a high-frequency electric field in a state that the dyeing liquids are un-dried to dye the portion applied with the dyeing liquids.
In the case where a fiber preliminary dyed with a certain color is partially dyed with another color according to the above process, there is a drawback that color controlling may be difficult due to an influence of the original color of the fiber preliminary dyed with the certain color. Also, a boundary portion of the dyed portions of the hair fiber obtained by the above process is not sufficiently gradated, and an intended color tone change or gradation may not be obtained.    Patent document 1: JP Hei 10-295942A